EP0166852B1 - Keramische PTC-Masse - Google Patents

Keramische PTC-Masse Download PDF

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Publication number
EP0166852B1
EP0166852B1 EP85101632A EP85101632A EP0166852B1 EP 0166852 B1 EP0166852 B1 EP 0166852B1 EP 85101632 A EP85101632 A EP 85101632A EP 85101632 A EP85101632 A EP 85101632A EP 0166852 B1 EP0166852 B1 EP 0166852B1
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EP
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Prior art keywords
ceramic composition
ptc
ptc ceramic
composition according
amount
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EP85101632A
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English (en)
French (fr)
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EP0166852A1 (de
Inventor
Noburu C/O Kabushiki Kaisha Toshiba Fukushima
Hisashi C/O Kabushiki Kaisha Toshiba Yoshino
Shunji C/O Kabushiki Kaisha Toshiba Nomura
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Toshiba Corp
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Toshiba Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient
    • H01C7/022—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient mainly consisting of non-metallic substances
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/02—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having positive temperature coefficient

Definitions

  • This invention relates to a ceramic composition for a PTC (positive temperature coefficient) resistor, more specifically to a ceramic composition for a PTC resistor which is characterized by having a small specific resistance in the state of a low resistance.
  • BaTi0 3 ceramics in which a variety of impurities are included.
  • BaTi0 3 ceramics in which La, Sm, Sb or Nb is included shows PTC properties that the relative resistance thereof increases about 10 4 times at around 250°C as compared with those of at ambient temperature (J. Mat. Sci., Vol. 6, p. 1214 (1971); W. Heywang).
  • These ceramics have as large an electric resistance as 10° Ocm or more in a low resistance condition and their PTC phenomenon depends on a mechanism which is based on grain boundary layers, therefore they can scarcely be utilized in fields utilizing a large electric power.
  • the compound V 1 0 3 in which Cr or AI is included has PTC properties of a specific resistance based on the fact that it transfers from a metallic state to an insulating state at a temperature of room temperature to about 200°C.
  • a V 203 single crystal in which Cr is included shows PTC properties that the relative resistance thereof increases from 10 -2 Ocm to 1 ⁇ cm with increasing temperature at around room temperature (Phys. Rev. B7, p. 1920 (1973); D. B. McWhan et al.) and in a V 2 0 3 single crystal in which AI is included, the same PTC properties as mentioned above have been observed (Phase Transitions, 1, P. 289 (1980); H. Kuwamoto & J. M.
  • a PTC ceramic composition comprising a V 2 0 3 component which contains additionally chromium or aluminium and a further added metal like Fe, Co, Ni or Cu.
  • This invention has been completed in view of the above-mentioned problems, and its object is to provide a ceramic composition for a PTC resistor which mainly comprises V 2 0 3 and which is improved in points of a sintering characteristics and PTC properties.
  • composition of this invention comprises a fundamental component represented by the formula: wherein x is a value within the range of 0 Z x ⁇ 0.02 and A is at least one of Cr and AI, and a further metal and is characterized in that the further added metal is tin in an amount of 1 to 25% by weight based on the total weight of the composition.
  • This invention is directed to a ceramic composition for a PTC resistor which comprises a component represented by the formula: wherein x is a value within the range of 0 Z x ⁇ 0.02 and A is at least one of Cr and AI, and tin in an amount of 1 to 25% by weight based on the weight of the fundamental component. That is, in this invention, tin (Sn) is added to the component (V 1-x A x ) 2 O 3 to prepare the ceramic composition having a heightened sintering characteristics and improved PTC properties.
  • Sn is stable as a metal at a sintering temperature of 1400 to 1600°C and in a sintering atmosphere, and serves to accelerate sintering when interposed among the grains of the compound (V 1-x A x ) 2 O 3 .
  • the sintered composition which has undergone a sintering treatment includes an Sn deposition phase therein by which a specific resistance of the PTC properties in a low resistance region is lowered and an current capacity is increased.
  • the reason why the respective components in the composition of this invention are quantitatively restricted to the above-mentioned range is as follows:
  • the amount x of the component A has a directed influence on the PTC properties, when being in the range of 0 ⁇ x 5 0.020.
  • the factor x is in the range of 0.001 ⁇ x Z 0.020.
  • the component A comprises Cr and/or AI, and when both of them are used, a ratio of one to another can be suitably decided, so long as the total amount of them is within the range of the above-mentioned amount x.
  • a ratio of Sn to the fundamental component (V 1-x A x ) 2 O 3 is within the range of 1 to 25% by weight, preferably 2.0 to 20.0% by weight.
  • the amount of the added Sn is less than 1% by weight, the effect of improving the sintering characteristics will not be obtained; when it is more than 25% by weight, a maximum value of the specific resistance of the PTC properties will be remarkably lowered and the magnification of a variation in the specific resistance will also be disadvantageously reduced.
  • a PTC element in which the ceramic composition of this invention is employed can be prepared as follows:
  • Usable materials for the ceramic composition include powdery metallic oxides such as V 2 O 5 , V 2 O 3 , Cr 2 0 3 , Al 2 O 3 and Sn0 2 .
  • the employment ofV203 as the vanadium oxide starting material is preferable since it can abbreviate a reduction procedure of the vanadium oxide whereby a particle growth or the aggregation of the particles at the reduction procedure from V 2 0, to V 2 0 3 are prevented.
  • V 2 0 5 or V 2 0 3 , Cr 2 0 3 , AI 2 0 3 and Sn0 2 are weighed, and they are then mixed and ground in, for example, a wet ball mill, followed by reducing.
  • V 2 0 5 When V 2 0 5 is used, it is reduced to V 2 0 3 .
  • the employment of the powder mainly comprising the produced V 2 0 3 permits effectively improving the uniformity of the ceramic composition.
  • a manner of adding tin to the fundamental component in the form of Sn0 2 and mixing them also allows the uniformity of the fundamental composition to be improved.
  • most of the added Sn0 2 is reduced to metallic tin.
  • an organic binder such as a paraffin or a polyvinyl alcohol (PVA) is added, and pressure molding is then carried out. Afterward, the molded material is sintered in a reducing atmosphere such as a hydrogen stream.
  • PVA polyvinyl alcohol
  • the thus obtained ceramic element which has densely been sintered is considered to be highly excellent, because of having a low specific resistance value in a low resistance condition.
  • the selection of the composition regarding this invention permits preparing the V 2 0 3 -based ceramics for a PTC resistor which have a small electric resistance in the low resistance state, good PTC properties, and a high density.
  • V 2 0 5 , Cr 2 0 3 , A1 2 0 3 and Sn0 2 powders were prepared and the respective components were weighed for samples (Nos. 1 to 5) regarding this invention in compositive proportions shown in Table 1. They were then mixed and ground for 45 hours in a wet ball mill. Afterward, reduction was carried out at 600°C for 2 hours and subsequently at 1000°C for 3 hours in a hydrogen stream. To the resulting powder, a paraffin dissolved in trichloroethylene was added as an organic binder, and pressure molding was then carried out. Next, the molded materials were sintered at 1400°C for 4 hours in the hydrogen stream to prepare the samples.
  • V 2 0 3 , Cr 2 0 3 , A1 2 0 3 and Sn0 2 powders were prepared and the respective components were weighed for samples (Nos. 8 to 12) regarding this invention in compositive proportions shown in Table 2. They were then mixed and ground for 12 hours in a wet ball mill. To the resulting powder, a paraffin dissolved in trichloroethylene was added as an organic binder, and they were dried. Next, the pressure molded materials were sintered at 1400°C for 4 hours in the hydrogen stream to prepare the samples.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Ceramic Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Conductive Materials (AREA)
  • Thermistors And Varistors (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Inorganic Insulating Materials (AREA)
  • Apparatuses And Processes For Manufacturing Resistors (AREA)

Claims (6)

1. Keramische PTC-Masse, welche eine Grundkomponente entsprechend der Formel:
Figure imgb0008
worin x einen Wert im Bereich von 0 Z x ≦ 0,02 bedeutet, und A mindestens eine Komponente von Cr und AI darstellt, und ein weiteres Metall umfasst, dadurch gekennzeichnet, dass diesses weiter zugegebene Metall Zinn in einer Menge von 1 bis 25 Gew.-%, bezogen auf das Gesamtgewicht der Masse, darstellt.
2. PTC-Keramikmasse nach Anspruch 1, worin die Komponente Zinn in einer Menge von 2,0 bis 20,0 Gew.-%, bezogen auf das Gesamtgewicht der Masse, enthalten ist.
3. PTC-Keramikmasse nach Anspruch 1, worin der genannte Faktor x im Bereich von 0,001 ≦ x ≦ 0,02 liegt.
4. PTC-Keramikmasse nach Anspruch 1, worin die genannte Grundkomponente der folgenden Formel entspricht:
Figure imgb0009
wobei x die vorstehend angegebene Bedeutung hat.
5. PTC-Keramikmasse nach Anspruch 1, worin die genannte Grundkomponente der folgenden Formel entspricht:
Figure imgb0010
wobei x die vorstehend angegebene Bedeutung hat.
6. PTC-Keramikmasse nach Anspruch 1, worin die Oxide der genannten jeweiligen Metalle als Materialien vermengt werden.
EP85101632A 1984-06-11 1985-02-14 Keramische PTC-Masse Expired EP0166852B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP59118207A JPS60262303A (ja) 1984-06-11 1984-06-11 Ｐｔｃセラミツク組成物
JP118207/84 1984-06-11

Publications (2)

Publication Number Publication Date
EP0166852A1 EP0166852A1 (de) 1986-01-08
EP0166852B1 true EP0166852B1 (de) 1988-09-07

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP85101632A Expired EP0166852B1 (de) 1984-06-11 1985-02-14 Keramische PTC-Masse

Country Status (5)

Country Link
US (1) US4642136A (de)
EP (1) EP0166852B1 (de)
JP (1) JPS60262303A (de)
KR (1) KR900004816B1 (de)
DE (1) DE3564884D1 (de)

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8529867D0 (en) * 1985-12-04 1986-01-15 Emi Plc Thorn Temperature sensitive device
KR910001317B1 (ko) * 1985-12-23 1991-03-02 가부시키가이샤 도시바 반도체소자의 보호회로
SE465524B (sv) * 1990-02-08 1991-09-23 Asea Brown Boveri Anordning foer oeverlast- och kortslutningsskydd i elektriska anlaeggningar
US5407603A (en) * 1992-06-04 1995-04-18 Minnesota Mining And Manufacturing Company Vanadium oxide colloidal dispersons and antistatic coatings
DE4425330A1 (de) * 1993-07-26 1996-01-25 Siemens Ag Schalter zur Strombegrenzung
DE4446045A1 (de) * 1994-12-22 1996-06-27 Siemens Ag Schalter zur Strombegrenzung
US6128168A (en) * 1998-01-14 2000-10-03 General Electric Company Circuit breaker with improved arc interruption function
US6144540A (en) * 1999-03-09 2000-11-07 General Electric Company Current suppressing circuit breaker unit for inductive motor protection
US6157286A (en) * 1999-04-05 2000-12-05 General Electric Company High voltage current limiting device
JP4819806B2 (ja) * 2004-07-14 2011-11-24 スリーエム イノベイティブ プロパティズ カンパニー カルボシランモノマーを含有する歯科用組成物

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CH581377A5 (de) * 1975-02-11 1976-10-29 Bbc Brown Boveri & Cie
EP0037859A1 (de) * 1980-04-16 1981-10-21 BBC Aktiengesellschaft Brown, Boveri & Cie. Gesintertes Kaltleitermaterial und Verfahren zu seiner Herstellung
JPS57157502A (en) * 1981-03-24 1982-09-29 Murata Manufacturing Co Barium titanate series porcelain composition

Also Published As

Publication number Publication date
US4642136A (en) 1987-02-10
JPS60262303A (ja) 1985-12-25
DE3564884D1 (en) 1988-10-13
KR860000675A (ko) 1986-01-30
KR900004816B1 (ko) 1990-07-07
EP0166852A1 (de) 1986-01-08

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